English

An iteration procedure for a two-term Machin-like formula for pi with small Lehmer's measure

General Mathematics 2017-07-28 v3

Abstract

In this paper we present a two-term Machin-like formula for pi π4=2k1arctan(1u1)+arctan(1u2)\frac{\pi}{4} = 2^{k - 1}\arctan\left(\frac{1}{u_1}\right) + \arctan\left(\frac{1}{u_2}\right) with small Lehmer's measure e0.245319e \approx 0.245319 and describe iteration procedure for simplified determination of the required rational number u2u_2 at k=27k = 27 and u1=85445659u_1 = 85445659. With these results we obtained a formula that has no irrational numbers involved in computation and provides 1616 digits of pi at each increment by one of the summation terms. This is the smallest Lehmer's measure ever reported for the Machin-like formulas for pi.

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Cite

@article{arxiv.1706.08835,
  title  = {An iteration procedure for a two-term Machin-like formula for pi with small Lehmer's measure},
  author = {S. M. Abrarov and B. M. Quine},
  journal= {arXiv preprint arXiv:1706.08835},
  year   = {2017}
}

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20 pages